The present invention relates to a navigation apparatus for mobile systems such as robots, and more particularly to a navigation apparatus which can move a mobile system to a destination by understanding the surroundings and can adapt itself to the environment.
Many robots presently are used in well-ordered environments such as factories. In recent years, however, a robot usable even in environments other than well-ordered environments has been required. In order to realize this requirement, the robot needs to be given an intelligence function and a movement function. Through the movement function, the robot can have its working limits extended and can also be moved to a place of adverse environmental conditions. For these reasons, various moving mechanisms which can travel over unlevel ground, a staircase, etc. have recently been proposed.
Meanwhile, with enhancement in the movement function, a navigation apparatus has been required which autonomously guides a robot to a desired destination. As an example of such a navigation apparatus, there is a system which employs an observed image information for guidance information (Proceedings of the 24th conference on remote systems technology, 1976, pp. 196-218). This navigation apparatus employing image information is such that an image obtained with a television camera or the like is processed to extract the feature points of the image, a determination of the three-dimensional arrangement of an object including directions, distances etc. is computed on the basis of the arrangement of the feature points, and the distance to the object is detected on the basis of the computation so as to derive a guidance signal which includes steering, speed etc. and with which the mobile system is guided.
With a navigation apparatus of this type, the processing of a large quantity of image information is involved, and a considerable period of time is needed for computing each processing step. Therefore, in guiding the mobile system at high speed, only some of the image information successively received can be utilized, so that the mobile system cannot be guided with high precision. Moreover, in the foregoing navigation apparatus, respective images are treated as being independent in the image processing as described above. Therefore, unintentional movement of the image ascribable to vibrations etc. has a direct influence in extracting a guidance signal for the mobile system, with the result that an exact guidance signal cannot be obtained.
For such reasons, the prior-art navigation apparatus has been used under a well-ordered situation in which vibrations hardly develop or a situation in which a fixed target object can be always utilized or a recognition pattern is employed. Moreover, it has been necessary to run the mobile system at low speed so that the surroundings can be sufficiently recognized. Consequently, the aforementioned navigation apparatus is unsuited for application to a mobile system which moves at high speed in general environments.